net: erspan: fix erspan config overwrite

When an erspan tunnel device receives an erpsan packet with different
tunnel metadata (ex: version, index, hwid, direction), existing code
overwrites the tunnel device's erspan configuration with the received
packet's metadata.  The patch fixes it.

Fixes: 1a66a836 ("gre: add collect_md mode to ERSPAN tunnel")
Fixes: f551c91d ("net: erspan: introduce erspan v2 for ip_gre")
Fixes: ef7baf5e ("ip6_gre: add ip6 erspan collect_md mode")
Fixes: 94d7d8f2 ("ip6_gre: add erspan v2 support")
Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/ip_gre.c

@@ -322,15 +322,6 @@ static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 			info = &tun_dst->u.tun_info;
 			info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
 			info->options_len = sizeof(*md);
-		} else {
-			tunnel->erspan_ver = ver;
-			if (ver == 1) {
-				tunnel->index = ntohl(pkt_md->u.index);
-			} else {
-				tunnel->dir = pkt_md->u.md2.dir;
-				tunnel->hwid = get_hwid(&pkt_md->u.md2);
-			}
-
 		}
 
 		skb_reset_mac_header(skb);

net/ipv6/ip6_gre.c

@@ -562,15 +562,6 @@ static int ip6erspan_rcv(struct sk_buff *skb, int gre_hdr_len,
 			ip6_tnl_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
 
 		} else {
-			tunnel->parms.erspan_ver = ver;
-
-			if (ver == 1) {
-				tunnel->parms.index = ntohl(pkt_md->u.index);
-			} else {
-				tunnel->parms.dir = pkt_md->u.md2.dir;
-				tunnel->parms.hwid = get_hwid(&pkt_md->u.md2);
-			}
-
 			ip6_tnl_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 		}